JPH0415579B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an unsaturated arc tube in which sodium, a metal for buffer gas, and a rare gas for starting aid are sealed in an arc tube made of a translucent ceramic tube, and the entire amount of the sealed metal evaporates under stable lighting conditions. This invention relates to a vapor pressure type high pressure sodium lamp with a built-in starter.

High-pressure sodium lamps are highly efficient and are widely used as power-saving light sources in fields such as factory lighting and road lighting. By the way, xenon gas is generally used as a starting aid gas in high-pressure sodium lamps.

The reason for this is that xenon gas has a lower thermal conductivity than other rare gases, so heat loss can be reduced and efficiency can be increased. However, high-pressure sodium lamps filled with xenon gas have a high starting voltage, requiring a high voltage pulse of approximately 4000V to start the lamp. Therefore, in general, a starter is used in combination with a ballast exclusively for high-pressure sodium lamps equipped with a pulse generator, or a starter is installed in the outer bulb, in which a bimetallic switch and a resistor are connected in series in parallel with the arc tube. A built-in high pressure sodium lamp is used. The latter type of high-pressure sodium lamp with a built-in starter has the advantage that it can be used with an inexpensive general high-pressure mercury lamp ballast compared to the former type of lamp combined with a dedicated ballast.

However, conventional high-pressure sodium lamps with built-in starters have a drawback in that they cannot be used with constant power type ballasts even with high-pressure mercury lamp ballasts. One of the reasons is that constant power ballasts for high-pressure mercury lamps have
Since the capacitor 12 is connected as shown in the figure, the pulse is likely to be absorbed and the lamp will not start reliably. Another reason is that conventional high-pressure sodium lamps with built-in starters are saturated vapor pressure discharge lamps, and the lamp voltage varies greatly with increases and decreases in lamp input. Constant power type ballasts for high pressure mercury lamps have constant current characteristics, so when used in combination with such saturated vapor pressure type discharge lamps, the lamp power becomes excessive and it is not possible to maintain stable lighting for a long time.

The present invention has been made in view of the above facts, and its object is to provide a high-pressure sodium lamp with a built-in starter that can be used in combination with a constant-power ballast for high-pressure mercury lamps.

The present invention will be described below with reference to the drawings.

Figure 1 shows a lighting circuit using a constant power ballast for high-pressure mercury lamps, where 11 is a lamp, 12 is a capacitor, and 1
3 is a resistor, 14 is a transformer, 15 is a choke coil, and 16 is a power source.

FIG. 2 is a circuit diagram of a conventional high-pressure sodium lamp with a built-in starter, in which 1 is a resistor, 2 is a bimetallic switch, and the two are connected in series to form the starter. 4 is an arc tube, 5 is a starting auxiliary conductor, 6 is a support wire, and 7 and 8 are connected to a cap (not shown) by stem lead wires. When a conventional high-pressure sodium lamp with a built-in starter is lit using the lighting circuit shown in Figure 1, current first flows through the starter circuit of the lamp, and the heat generated by the resistor 1 causes the normally closed bimetal switch 2 to be turned on. is heated. After a certain period of time has passed, bimetal switch 2 closes, and at this time,
The sudden change in current generates a pulsed voltage across the chiyoke coil 5, and this pulsed voltage is applied to the lamp. However, in this lighting circuit, the lamp glow discharges only when a pulse voltage is applied, but does not transition to arc discharge, and therefore the lamp does not start.

The inventors of the present invention conducted a detailed investigation into the reasons why the lamp does not start as described above, and as a result, the following two phenomena were mainly observed.

(1) The pulse voltage is attenuated between the chiyoke coil 15 and the lamp 11.

(2) Since the pulse voltage is generated only sporadically, there is no transition from glow discharge to arc discharge.

As a result of conducting various tests to determine the reasons why the lamp does not start, it was discovered that a high-pressure sodium lamp with a built-in starter that can be reliably started can be obtained in combination with a constant-power ballast for high-pressure mercury lamps.

FIG. 3 is a circuit diagram of a high-pressure sodium lamp with a built-in starter according to the present invention. In the figure, 1 is a resistor, 2 is a bimetal switch, and 3 is a lighting tube, each of which is connected in series to form a starter, and is connected in parallel with an arc tube 4. 5 is a starting auxiliary conductor;
6 is a support wire, and 7 and 8 are connected to a base (not shown) by stem lead wires. When the high-pressure sodium lamp with a built-in starter according to the present invention configured as described above is lit using the lighting circuit shown in FIG. 1, the operation of the lamp is as follows. When a voltage is applied through the ballast between 7 and 8, the resistance 1
Current flows through the bimetal switch 2 and the starter circuit of the lighting tube 3. After a certain period of time has elapsed, the lighting tube 3 is activated and the current flowing through the starter circuit is turned on and off in short cycles. In response to this rapid change in current, a pulse voltage is generated across the choke coil 15 and applied to both ends of the lamp.

Bimetal switch 2 built into the starter circuit
serves to protect the lighting tube and lighting circuit during restart. That is, when the lamp is turned off from a stable lighting state and immediately turned on, the starting voltage of the lamp is high and the lamp will not turn on even if the lighting tube operates. Approximately 5 minutes of cooling time is required for the lamp to restart. Therefore, without the bimetal switch 2, the lighting tube will continue to operate for about 5 minutes after the light is turned off, which will shorten the life of the lighting tube and cause unnecessary high voltage pulses to be applied to the lighting circuit, leading to insulation deterioration. Become. By turning on the bimetal switch 2, this inconvenience can be eliminated.

Next, an example of a high-pressure sodium lamp with a built-in starter that is lit with a constant power type ballast for a 400W high-pressure mercury lamp will be described. In Figure 3, 1 is approximately 250Ω
The resistors 3 and 3 are lighting tubes with an operating voltage of about 160V, and are connected in series with the bimetal switch 2 to form a starter. 4 is an arc tube made of a translucent alumina tube with an inner diameter of 8 mm and a length of 115 mm, filled with 0.05 mg of sodium, 5 mg of mercury, and 100 torr of xenon gas as a rare gas for starting aid, and 5 is a starting aid conductor made of a 0.5φ molybdenum wire. It is. When three high-pressure sodium lamps with a built-in starter according to the present invention constructed in this way were lit in combination with a constant power ballast for a 400W high-pressure mercury lamp consisting of the circuit shown in FIG. 1, the lamps started reliably. The characteristics of the lamp at this time were as follows.

At a constant power supply voltage of 200V Lamp No. 1 2 3 Lamp current 3.41A 3.50 3.51 Lamp voltage 124V 127 128 Lamp power 363W 390 395 On the other hand, the configuration of the starter is the same as that of the present invention, and the arc tube has a saturated vapor pressure. When three lamps using the same shape were lit using the lighting circuit shown in Figure 1, the lamp characteristics were as follows.

At a constant power supply voltage of 200V Lamp No. 1 2 3 Lamp current 3.60A 3.54 Turning off Lamp voltage 225V 142.2 Lamp power 665W 440 As described above, some saturated vapor pressure discharge lamps may have excessive pulse power or turn off. Although it cannot be stably lit, the high-pressure sodium lamp with a built-in starter using the present invention is an unsaturated vapor pressure discharge lamp, so there is no change in lamp voltage due to changes in lamp input, and the constant power for high-pressure mercury lamps is maintained. Can be used in combination with a shape ballast for stable lighting.

Furthermore, tests were conducted on the xenon filling pressure and startability of lamps that were different in the xenon gas filling pressure but were otherwise identical to those in the example. They found that if the xenon gas filling pressure exceeded 150 Torr, the lamp would be difficult to start, but the xenon gas It has been found that the lamp will start reliably if the pressure is below 150 torr. On the other hand, in the conventional high-pressure sodium lamp with a built-in starter shown in Figure 2, even if the pressure of the xenon gas sealed in the arc tube was 100 Torr or less, the lamp would not start with the lighting circuit shown in Figure 1. .

From these test results, the reason why the high-pressure sodium lamp with a built-in starter according to the present invention can be lit in combination with a constant-power ballast for high-pressure mercury lamps is that the pulse voltage from the lighting tube is shorter and more numerous than that from a bimetal switch. This is considered to be because even if the pulse is partially absorbed by capacitor 12 or transformer 14 in FIG. 1, it still has enough energy to discharge the lamp.

As explained above, the present invention is an unsaturated vapor pressure type high-pressure sodium lamp in which the arc tube is filled with sodium, a metal for buffer gas, and a rare gas for starting aid, and the entire amount of the sealed metal is evaporated in a stable lighting state. The invention is characterized in that a starter consisting of a lighting tube and a resistor connected in series in parallel with the arc tube is incorporated in the outer bulb together with the arc tube, and in combination with a constant power type ballast for a high pressure mercury lamp. It has the feature of being able to be lit, and has great industrial value.

Although Figure 1 is a circuit diagram of a constant power ballast for high pressure mercury lamps, this is just an example. I get the same result.

[Brief explanation of drawings]

FIG. 1 shows a lamp lighting circuit using a constant power type ballast for a high-pressure mercury lamp, where 11 is a lamp, 12 is a capacitor, 14 is a transformer, and 15 is a chiyoke coil. FIG. 2 is a circuit diagram of a conventional high-pressure sodium lamp with a built-in starter, in which 1 is a resistor, 2 is a bimetallic switch, 4 is an arc tube, and 9 is an outer bulb. FIG. 3 is a circuit configuration diagram showing an embodiment of the present invention, and 3 is a lighting tube.

Claims (1)

[Scope of Claims] 1. An arc tube filled with sodium, a metal for buffer gas, and a rare gas for starting aid, in which the entire amount of the enclosed metal evaporates in a stable lighting state, and a lighting device connected in parallel with the arc tube. A high voltage with built-in starter, characterized in that a starter consisting of a series circuit of a tube and a resistor is built into the outer tube, and the lamp is lit in combination with a constant power ballast for high pressure mercury lamps with a capacitor connected in series. Sodium lamp. 2. Use 150 xenon gas as a rare gas for starting aid.
A high-pressure sodium lamp with a built-in starter according to claim 1, characterized in that the lamp is sealed at a pressure below Torr.